There is a need for a light weight building element which in its own right has structural integrity and which can be coupled with other such light building elements for the purposes of building panels, walls and various structural components in the formation of buildings.
It is an important consideration that such structural elements have significant strength and should have a reasonably high resistance to fire.
Classically in order to provide both the compressive strength and the tensile strength required of building elements, steel reinforcement (which has tensile strength) has been provided within concrete (which has compressive strength). However the resulting elements, because of the density of the concrete, have been heavy and not readily manipulable when manufactured in the form of prefabricated panels, columns and the like.
This problem of the weight of composite steel in concrete structures is not solved by using a low density material such as aerated concrete to carry the compressive loads. This is because steel-reinforced concrete relies on bonding between the concrete and the steel reinforcing. This bonding effect is not possible with aerated concrete. The light weight of aerated concrete is achieved by the presence of air pockets within the bulk of the concrete. The presence of these air pockets results in a lower steel to concrete bonding area, and far less effective bonding. There are similar difficulties in obtaining adhesion or bonding between reinforcing steel and other light weight alternatives to conventional concrete.